Catalyst and method for direct conversion of syngas to light olefins

ABSTRACT

Direct conversion of syngas to light olefins is carried out in a fixed bed or a moving bed reactor with a composite catalyst A+B. The active ingredient of catalyst A is active metal oxide; and catalyst B is one or more than one of zeolite of CHA and AEI structures or metal modified CHA and/or AEI zeolite. A spacing between geometric centers of the active metal oxide of the catalyst A and the particle of the catalyst B is 5 μm-40 mm. A spacing between axes of the particles is preferably 100 μm-5 mm, and more preferably 200 μm-4 mm. A weight ratio of the active ingredients in the catalyst A and the catalyst B is within a range of 0.1-20 times, and preferably 0.3-5.

TECHNICAL FIELD

The present invention belongs to preparation of light olefins usingsyngas, and particularly relates to a catalyst and a method forpreparing light olefins from direct conversion of syngas.

BACKGROUND

Light olefins refer to alkenes with the number of carbon atoms less thanor equal to 4. Light olefins represented by ethylene and propylene arevery important basic organic chemical raw materials. With the fastgrowth of economy in China, the market of the light olefins is in shortsupply for a long time. At present, the light olefins are producedmainly through a petrochemical route of cracking of light hydrocarbons(ethane, naphtha and light diesel fuel). Due to the increasing shortageof global petroleum resources and the long-term high price of crude oil,the development of the light olefins industry relying only on a tubularcracking furnace technology based on petroleum light hydrocarbons as rawmaterial will encounter more and more difficulties in raw material. Thetechnology and the raw material for producing the light olefins must bediversified. The source of the raw material can be widen by technologiesbased on syngas for the production of light olefins, which can bederived from crude oil, natural gas, coal and renewable materials, thusprovide an alternative solution for the steam cracking technology basedon the high-cost raw materials like naphtha. One-step direct preparationof the light olefins using the syngas is a process of directly preparingthe light olefins with the number of carbon atoms less than or equal to4 through Fischer-Tropsch synthesis reaction of carbon monoxide andhydrogen under the action of the catalyst. This process simplifies theprocess flow and greatly reduces the investment unlike an indirectmethod that further prepares the alkene from the syngas through themethanol or dimethyl ether.

Direct preparation of light olefins using syngas through Fischer-Tropschsynthesis has become one of research hotspots in the development ofcatalysts for Fischer-Tropsch synthesis. In patent CN1083415A disclosedby Dalian Institute of Chemical Physics, Chinese Academy of Sciences,high activity (CO conversion rate: 90%) and selectivity (light olefinsselectivity: 66%) can be obtained under reaction pressure of 1.0 to 5.0MPa and reaction temperature of 300 to 400° C., catalyzed by aniron-manganese catalyst system, with IIA alkali metal oxide such as MgOor silica rich zeolite (or phosphorous-aluminum zeolite) as the support,and alkali K or Cs ion as the auxiliary. In patent ZL03109585.2 declaredby Beijing University of Chemical Technology, Fe/activated carboncatalyst with manganese, copper, zinc, silicon or potassium asauxiliaries is prepared by a vacuum impregnation method for the reactionof preparation of the light olefins from the syngas. Under thiscatalyst, the CO conversion rate is 96%, and the selectivity of lightolefins in hydrocarbons is 68%, with no feedstock gas circulation.Recently, Professor de Jong's team at Utrecht University in Netherlandsmade good progress by using Fe catalyst modified byFe, Naor S, andsupported on SiC, carbon nanofiber or other inert carriers, obtained 61%of selectivity of light olefins. However, the selectivity of lightolefins will reduce when the syngas conversion increases. In directpreparation of alkenes from syngas, cryogenic separation is generallyneeded due to the gaseous raw material and low-boiling ethylene product.If C₃-C₄ alkenes, i.e., propylene and butylene, can be obtained withhigh selectivity, cryogenic separation will not be needed, therebygreatly reducing energy consumption and cost for product separation andbringing great application value. In the above reports, metal iron oriron carbide was applied as the active component of the catalyst, andthe reactions followed the carbon chain growth mechanism on metalsurfaces. The selectivity of the product light olefins is low, while theselectivity of C₃-C₄ alkene is lower.

Recently, a bifunctional catalyst with the composite of ZnCr₂O₄ oxideand hierarchical pore SAPO-34 zeolite has been reported by DalianInstitute of Chemical Physics, Chinese Academy of Sciences (Jiao et al.,Science 351 (2016) 1065-1068), which realized 80% of the selectivity oflight olefins when the CO conversion was 17%. The selectivity of lightparaffins was 14% so the olefin/paraffin ratio of light hydrocarbons(o/p) was 5.7. When CO conversion increased to 35%, the selectivity oflight olefins was 69%, the selectivity of light paraffins was 20%,making an o/p of 3.5, and propylene and butylene selectivity was 40-50%.

SUMMARY

In view of the above problems, the present invention provides a catalystand a method for preparing light olefins by direct conversion of syngas.

The technical solution of the present invention is as follows:

A catalyst, characterized in that, the catalyst is a composite catalystA+B and is formed by compounding catalyst A and catalyst B in amechanical mixing mode; the active ingredient of the catalyst A isactive metal oxide; the catalyst B is a zeolite of CHA and/or AEItopology; and the active metal oxide is one or more than one of MnO,MnCr₂O₄, MnAl₂O₄, MnZrO₄, ZnO, ZnCr₂O₄, ZnAl₂O₄, CoAl₂O₄ and FeAl₂O₄.

A spacing between geometric centers of the active metal oxide of thecatalyst A and the particle of the catalyst B is 5 μm-40 mm. A spacingbetween axes of the particles is preferably 100 μm-5 mm, and morepreferably 200 μm-4 mm.

A weight ratio of the active ingredients in the catalyst A and thecatalyst B is within a range of 0.1-20 times, and preferably 0.3-5.

The active metal oxide is composed of grains with a size of 5-30 nm, anda large amount of oxygen vacancies exist within a distance range of 0.3nm from the surfaces of the grains to the internal direction of thegrains, i.e., the molar weight of oxygen atoms occupies a value lessthan 80% compared with the theoretical stoichiometric ratio; andpreferably, the molar weight of oxygen atoms occupies a value of 80%-10%of the oxygen molar content in theoretical stoichiometric ratio, morepreferably 60%-10% and most preferably 50%-10%. The surface oxygenvacancies are defined as: (1−the molar weight of oxygen atoms intheoretical stoichiometric ratio of oxygen molar weight); andcorresponding oxygen vacancy concentration is preferably 20%-90%, morepreferably 40%-90% and most preferably 50%-90%.

A dispersing agent is also added to the catalyst A; the dispersing agentis one or more than one of Al₂O₃, SiO₂, Cr₂O₃, ZrO₂ and TiO₂; the activemetal oxide is dispersed in the dispersing agent; and the content of thedispersing agent in the catalyst A is 0.05-90 wt %, and the balance isthe active metal oxide.

The catalyst component B is a zeolite of CHA and/or AEI topology. TheCHA and/or AEI zeolite has eight-membered ring orifices and athree-dimensional porous channel and comprises cha cage.

The skeleton element composition of the zeolite of CHA and AEItopologies may be one or more than one of Si—O, Si—Al—O, Si—Al—P—O,Al—P—O, Ga—P—O, Ga—Si—Al—O, Zn—Al—P—O, Mg—Al—P—O and Co—Al—P—O.

H may be connected or not connected to the O element of the zeoliteskeleton. The H may be entirely or partially replaced by one or morethan one of Na, Ca, K, Mg, Ge, Zr, Zn, Cr, Ga. Sn, Fe, Co, Mo and Mn byion exchange; and the total molar ratio of the substitute metal tooxygen is 0.0002-0.001.

A molar ratio of (Si+Zn+Mg+Co) to (Al+Ga) in the zeolite compositionSi—O of the CHA topology and in the skeleton element composition outsideis less than 0.6.

A molar ratio of (Si+Zn+Mg+Co) to (Al+Ga) in the zeolite compositionSi—O of the AEI topology and in the skeleton element composition outsideis less than 0.6.

The zeolite has the amount of medium-strength acidic sites of 0-0.3mol/kg, preferably 0.003-0.2 mol/kg, and more preferably 0.003-0.06mol/kg, wherein the peak temperature range corresponding to thedesorption peak of NH3-TPD for mediate strong acid is 275-500° C., andpreferably 275-370° C.

The acid strength is defined by the peak temperature of NH₃-TPD,including three kinds of acid:weak acid, medium-strength acid and strongacid.

The NH₃-TPD is according to the position of a desorption peak of NH₃;the position of the desorption peak means that under standard testconditions that a ratio of sample mass w and carrier gas flow rate f(w/f) is 100 g·h/L and a heating rate is 10° C./min, a TCD records athermal conductivity signal of desorption of NH₃ and draws a desorptioncurve; according to the peak temperatures of the NH₃ desoption curve,the acid strength of inorganic solid is divided into three kinds; theweak acid is an acid site where the deposition temperature of NH₃ isless than 275° C.; the medium-strength acid is an acid site where thedeposition temperature of NH₃ is between 275° C. and 500° C.; and thestrong acid is an acid site where the deposition temperature of NH₃ isgreater than 500° C.

The mechanical mixing can adopt one or more than one of mechanicalagitation, ball milling, rocking bed mixing and mechanical grinding forcomposition.

A method for preparing light olefins using direct conversion of syngas,wherein syngas is used as reaction raw material; a conversion reactionis conducted on a fixed bed or a moving bed; and the adopted catalyst isthe catalyst of any one of claims 1-8.

The pressure of the syngas is 0.5-10 MPa; reaction temperature is300-600° C.; and space velocity is 300-10000 h⁻¹.

The ratio of syngas H₂/CO for reaction is 0.2-3.5, and preferably0.3-2.5.

The dual-function composite catalyst is used for preparing lower alkeneusing one-step direct conversion of syngas, wherein the selectivity forpropylene and butylene is 40-75%, and preferably 50-75%, while theselectivity for methane side product is lower than 15%, and preferablyless than 10%.

The present invention has the following beneficial effects that:

Different from the traditional technology for preparing the lightolefins through methanol (MTO for short), this technology realizes thepreparation of light olefins through one-step direct conversion ofsyngas.

Propylene and butylene selectivity is as high as 40-75%. The productscan be separated without deep cooling, thereby greatly reducingseparation energy consumption and cost.

The composite catalyst in the patent is simple in preparation processand mild in conditions. The creaction process has an extremely highproduct yield and selectivity, with the selectivity for C₂-C₄ lightolefins reaching 50-90% and especially high selectivity for C₃-C₄alkenes. Meanwhile, the selectivity for methane side product is low(<15%), and the catalyst has a long lifetime greater than 700 hours. Thepresent invention has excellent application prospect.

DETAILED DESCRIPTION

The present invention is further illustrated below by embodiments, butthe scope of claims of the present invention is not limited by theembodiments. Meanwhile, the embodiments only give some conditions forachieving the purpose, but it doesn't mean that the conditions must besatisfied to achieve the purpose.

Embodiment 1

I. Preparation of Catalyst A

(I) Synthesizing ZnO Material with Polar Surface Through an EtchingMethod:

(1) weighing 0.446 g (1.5 mmol) of Zn(NO₃)₂.6H₂O; weighing 0.480 g (12mmol) of NaOH and adding to the above container; weighing 30 ml ofdeionized water and adding to the container; stirring for a time greaterthan 0.5 h to uniformly mix a solution; increasing the temperature to160° C. with the reaction time of 20 h; decomposing precipitate intozinc oxide; naturally cooling to room temperature; centrifugallyseparating reaction liquid to collect the centrifugally separatedprecipitate; and washing with deionized water twice to obtain ZnO oxide;

(2) ultrasonically mixing an etching agent with ZnO oxide uniformlyunder normal temperature; immersing the ZnO oxide in the solution of theetching agent; and generating a complexing or direct reduction reactionby the etching agent and the zinc oxide; and

heating the above suspended matter; then taking out the suspended matterfor washing and filtering the suspended matter to obtain active nano ZnOmaterial having a large amount of surface oxygen holes.

In Table 1: the mass ratio of the catalyst to the etching agent is 1:3.The mass ratio of the oleic acid to the hexamethylenetetramine is 1:1,without solvent. The mass ratio of the oleic acid to the hydrazinehydrate is 95:5, without solvent. Specific treatment conditions includetemperature, treatment time and atmosphere types as shown in Table 1below.

(3) Drying or Drying and Reducing:

after centrifuging or filtering the above obtained products and washingthe products with deionized water, drying or drying and reducing theproducts in an atmosphere which is inert atmosphere gas or a gas mixtureof inert atmosphere gas and a reducing atmosphere, wherein the inertatmosphere gas is one or more than one of N₂, He and Ar, the reducingatmosphere is one or both of H₂ and CO, a volume ratio of the inertatmosphere gas to the reducing gas in the drying and reducing gasmixture is 100/10-0/100, the temperature of drying and reducing is 350°C., and time is 4 h. ZnO material with abundant oxygen vacancies on thesurface is obtained. Specific samples and preparation conditions thereofare shown in Table 1 below. The oxygen vacancies on the surface are:100%-percent of the molar weight of oxygen atoms in theoreticalstoichiometric ratio of oxygen molar weight.

TABLE 1 Preparation of ZnO Material and Parameter Performance Drying orDrying and Reducing Surface Sample Temperature/° C. and Temperature/° C.Oxygen Number Etching Agent Carrier Gas (V/V) Time/Minute and AtmosphereVacancy ZnO 1 oleic 100, N₂ 30 30, N₂ 21% acid-hexamethylenetetramineZnO 2 oleic acid 100, 5% H₂/N₂ 30 300, 5% H₂/N₂ 45% ZnO 3 oleic acid120, 5% CO/Ar 60 350, 5% CO/Ar 67% ZnO 4 oleic acid-5 wt % hydrazine140, 5% H₂/Ar 60 310, 5% H₂/Ar 73% hydrate ZnO 5 quadrol 100, 5% NH₃/Ar30 250, 5% NH₃/Ar 30% ZnO 6 quadrol 140, 5% NO/Ar 90 150, 5% NO/Ar 52%ZnO 7 20 wt % ammonium 100, Ar 30 120, 5% CO/Ar 22% hydroxide ZnO 8 20wt % ammonium 140, 5% NH₃/5% NO/Ar 90 400, He 29% hydroxide

The surface oxygen vacancies are the percent of the molar weight ofoxygen atoms in theoretical stoichiometric ratio of oxygen molar contentwithin a distance range of 0.3 nm from the surfaces of the grains to theinternal direction of the grains. The surface oxygen vacancies aredefined as: 100%-percent of the molar weight of oxygen atoms intheoretical stoichiometric ratio of oxygen molar weight.

As a reference example, ZnO 9 which is not etched in step (2) and has nooxygen vacancy on the surface; and metal Zn 10 by completely reducingZn. (II) Synthesizing MnO material with polar surface through an etchingmethod: the preparation process is the same as that of the above ZnO.The difference is that, the precursor of Zn is changed for thecorresponding precursor of Mn, which is one of manganous nitrate,manganese chloride and manganese acetate (manganous nitrate herein).

The etching process is the same as step (2) in above (I), and theprocess of drying or drying and reducing is the same as the preparationprocesses of products ZnO 3, ZnO 5 and ZnO 8 in step (3) in above (I).The catalyst having a great number of surface oxygen vacancies issynthesized. The surface oxygen vacancies are 67%, 29% and 27%.

Corresponding products are defined as MnO 1-3.

(III) Synthesizing Nano ZnCr₂O₄, ZnAl₂O₄, MnCr₂O₄, MnAl₂O₄ and MnZrO₄Spinel with High Specific Surface Area and High Surface Energy:

selecting corresponding nitrate, zinc nitrate, aluminum nitrate, chromicnitrate and manganous nitrate as precursors according to chemicalcomposition of the spinel, and mixing the precursors with urea at roomtemperature in water; aging the above mixed liquid; then taking out themixed liquid for washing, filtering and drying the obtainedprecipitants; and calcining the obtained solid under an air atmosphereto obtain spinel oxide which grows along the (110) crystal planedirection. The sample is also treated by the etching method tosynthesize the catalyst with a great number of surface oxygen vacancies.The etching process and aftertreatment process are the same as step (2)and step (3) in above (I). The sample has large specific surface areaand many surface defects, and can be applied to catalyzing theconversion of syngas.

Specific samples and preparation conditions thereof are shown in Table 2below. Similarly, the surface oxygen vacancies are defined as:100%-percent of the molar weight of oxygen atoms in theoreticalstoichiometric ratio of oxygen molar weight.

TABLE 2 Preparation of Spinel Material and Performance ParametersStoichiometric Ratio of Metal Elements in Spinel and Molar EtchingAgent, Concentration of one Aging Calcining Temperature/° C., Metal inWater Temperature ° C. Temperature ° C. Atmosphere and Surface OxygenSample Number (mmol/L) and Time h and Time h Time/min Vacancy spinel 1ZnCr = 1:2, Zn is 50 mM 120, 24 600, 48 oleic acid, 120, 41% 5% H₂/Ar,60 spinel 2 ZnAl = 1:2, Zn is 50 mM 130, 20 700, 24 oleic acid, 120, 72%5% H₂/Ar, 60 spinel 3 MnCr = 1:2, Mn is 50 mM 140, 18 750, 16 oleicacid, 120, 83% 5% H₂/Ar, 60 spinel 4 MnAl = 1:2, Mn is 50 mM 145, 16800, 10 oleic acid, 120, 20% 5% H₂/Ar, 60 spinel 5 MnZr = 1:2, Mn is 50mM 150, 12 900, 3  oleic acid, 120, 24% 5% H₂/Ar, 60

(IV) Cr₂O₃, Al₂O₃ or ZrO₂ Dispersed Active Metal Oxide

Preparing Cr₂O₃, Al₂O₃ or ZrO₂ dispersed active metal oxide through aprecipitate deposition method by taking Cr₂O₃, Al₂O₃ or ZrO₂ ascarriers. Taking the preparation of dispersed ZnO as an example,commercial Cr₂O₃, Al₂O₃ or ZrO₂ carrier is dispersed in a base solutionin advance, and then one or more than one of zinc acetate, zinc nitrate,zinc sulfate and other Zn precursors are taken as Zn raw material, mixedwith one or more than one of sodium hydroxide, ammonium bicarbonate,ammonium carbonate and sodium bicarbonate, and precipitated at roomtemperature. Herein, taking zinc nitrate and sodium hydroxide as anexample, the molar concentration of Zn²⁺ in the reaction liquid is0.067M; the ratio of molar fractions of Zn²⁺ and precipitant may be 1:8;and then aging is conducted at 160° C. for 24 hours to obtain carrierCr₂O₃, Al₂O₃ or ZrO₂ dispersed ZnO oxide, and the contents of thedispersing agents in catalyst A are 0.1 wt %, 10 wt % and 90 wt %.

The etching process is the same as the preparation processes of productsZnO 3, ZnO 5 and ZnO 8 in step (2) in above (I). The catalyst having agreat number of surface oxygen vacancies is synthesized. The surfaceoxygen vacancies are 65%, 30% and 25%. The aftertreatment process is thesame as step (3) in above (I).

Corresponding products from top to bottom are defined as dispersedoxides 1-3.

The same method is used to obtain carrier Cr₂O₃, Al₂O₃ or ZrO₂ dispersedMnO oxide, wherein the contents of the dispersing agents in catalyst Aare 5 wt %, 30 wt % and 60 wt %. The surface oxygen vacancies are 62%,27% and 28%. Corresponding products from top to bottom are defined asdispersed oxides 4-6.

II. Preparation of Catalyst B (Zeolite of CHA and AEI Topologies):

The CHA and/or AEI topology has eight-membered ring orifices and athree-dimensional porous channel and comprises cha cage.

1) The Specific Preparation Process is as Follows:

The raw materials of 30% silica sol (mass concentration), AlOOH,phosphoric acid, TEA (R) and deionized water are weighed according tothe oxide SiO₂:Al₂O₃:H₃PO₄:R:H₂O=1.6:16:32:55:150 (mass ratio); aftermixing at room temperature, auxiliary HF is added with a molar weight of0.5 time of the template agent; the mixture is stirred and aged at 30°C. for 2 h, and transferred into a hydrothermal reactor and crystallizedat 200° C. for 24 h. The autoclave is quenched by water bath to roomtemperature. Centrifugal washing is conducted repeatedly until the pH ofthe supernatant is 7 at the end of washing. After the precipitate isdried at 110° C. for 17 h, the precipitate is calcined in air at 600° C.for 3 h to obtain the silicon-phosphorus-aluminum inorganic solid acidwith hierarchical pore structure.

The skeleton element composition of the zeolite of CHA and AEItopologies may be one or more than one of Si—O, Si—Al—O, Si—Al—P—O,Al—P—O, Ga—P—O, Ga—Si—Al—O, Zn—Al—P—O, Mg—Al—P—O and Co—Al—P—O.

O element of part of the skeleton is connected with H, and correspondingproducts are successively defined as zeolites 1-7.

TABLE 3 Preparation of Zeolite of CHA or AEI Topology and PerformanceParameters Tem- Hydrothermal Deposition Sample Si Aluminum plateTemperature Time Acid Temperature Number Source Source P Source AgentAuxiliary Mass Ratio (° C.) (Day) Amount of NH₃ Zeolite 1 TEOS SodiumPhosphoric TEA SiO₂:Al₂O₃:H₃PO₄:R:H₂O = 180 1 0.25 349 Meta- Acid1.6:16:32:55:150 aluminate Zeolite 2 Silica Al(OH)₃ Phosphoric Mor HClSiO₂:Al₂O₃:H₃PO₄:R:H₂O = 150 4 0.27 365 Sol Acid 2.4:19:30:15:150Zeolite 3 TEOS AlOOH Phosphoric TEAOH HF SiO₂:Al₂O₃:H₃PO₄:R:H₂O = 160 40.13 350 Acid 0.7:15:32:55:150 Zeolite 4 Silica Aluminium PhosphoricDIPEA SiO₂:Al₂O₃:H₃PO₄:R:H₂O = 170 2.5 0.23 355 Sol Isopropoxide Acid1.1:17:32:55:150 Zeolite 5 Aluminum Phosphoric TEAOH HFAl₂O₃:H₃PO₄:R:H₂O = 190 1 0.006 331 Sulfate Acid 16:32:55:150 Zeolite 6Silica Aluminum Phosphoric DIPEA SiO₂:Al₂O₃:H₃PO₄:R:H₂O = 200 1 0.078344 Sol Nitrate Acid 0.5:17:32:55:150 Zeolite 7 TEOS Aluminum PhosphoricTEA HF SiO₂:Al₂O₃:H₃PO₄:R:H₂O = 170 0.7 0.055 347 Sulfate Acid0.3:18:32:55:150 Zeolite 8 Aluminum Phosphoric TEA HCl Al₂O₃:H₃PO₄:R:H₂O= 160 3.5 0.014 339 Nitrate Acid 11:32:55:150

2) The H connected to the O element of skeletons of the above products1-7 is partly replaced by the following metal ions: Na, Ca, K, Mg, Ge,Zr, Zn, Cr, Ga. Sn, Fe, Co, Mo and Mn by ion exchange; and thepreparation process is:

SiO₂:Al₂O₃:H₃PO₄:R:H₂O=1.1:16:32:55:150 (molar ratio), wherein R is thetemplate agent.

The aluminum sulphate is mixed with the sodium hydroxide solution, andthen silica sol, phosphoric acid, TEA(R) and deionized water are addedand stirred for 1 h to obtain initial gel with uniform phase. Then, themixture is transferred into a synthesis autoclave, is staticallycrystallized at 165° C. for 80 h, and then is quenched, washed and driedto obtain a zeolite sample. The above samples are then mixed with 0.5mol/L of metal ion nitrate solution to be exchanged with thesolid-liquid mass ratio of 1:30. The mixture is stirred at 80° C. for 6h, washed and dried. The exchange procedure is conducted twicecontinuously, and the as-prepared powder is calcined at 550° C. for 3 hto obtain CHA or AEI zeolite after metal ion exchange.

Corresponding products are successively defined as zeolites 9-22.

TABLE 4 Preparation of Zeolite of CHA or AEI Topology and PerformanceParameters Ratio of Deposition Sample metal ion Exchange Time AcidTemperature of Number Ion and O NH₃-zeolites Aluminum Source Temperature(° C.) (hour) Amount NH₃ zeolite 9 Na 0.04 Zeolite 1 Sodium 80 8 0.23367 Metaaluminate Zeolite Ca 0.02 Zeolite 2 Al(OH)₃ 90 7 0.03 364 10Zeolite K 0.01 Zeolite 3 AlOOH 80 7 0.11 357 11 Zeolite Mg 0.015 Zeolite4 Aluminium 90 5 0.08 355 12 Isopropoxide Zeolite Ge 0.075 Zeolite 5Aluminum 80 7 0.15 367 13 Sulfate Zeolite Zr 0.03 Zeolite 6 Aluminum 907 0.05 347 14 Sulfate Zeolite Zn 0.005 Zeolite 7 Aluminum 80 8 0.10 37015 Sulfate Zeolite Cr 0.07 Zeolite 8 Aluminum 70 3 0.25 363 16 NitrateZeolite Ga 0.01 Zeolite 1 Aluminum 80 6 0.17 354 17 Nitrate Zeolite Sn0.001 Zeolite 2 AlOOH 60 5 0.27 357 18 Zeolite Fe 0.0005 Zeolite 3Aluminum 70 5 0.23 366 19 Nitrate Zeolite Co 0.0003 Zeolite 4 Aluminum80 6 0.18 367 20 Nitrate Zeolite Mo 0.0005 Zeolite 5 Aluminum 70 3 0.28369 21 Nitrate Zeolite Mn 0.002 Zeolite 6 AlOOH 70 8 0.29 359 22

TABLE 5 Preparation of Zeolite Composed of Other Elements andPerformance Parameters Sample Template Number Precursor 1 Precursor 2Precursor 3 Agent Auxiliary Mass Ratio Zeolite TEOS TEA HF SiO₂:R:H₂O =1.6:55:150 23 Zeolite Silica Sol Al(OH)₃ Mor HF SiO₂:Al₂O₃:R:H₂O =2.4:19:15:150 24 Zeolite Gallium Phosphoric TEAOH HF Ga2O3:H₃PO₄:R:H₂O =25 Nitrate Acid 15:32:55:150 Zeolite Silica Sol Gallium Phosphoric TEAHF SiO₂:Ga₂O₃:H₃PO₄:R:H₂O = 26 Nitrate Acid 1.1:17:32:55:150 ZeoliteZinc Aluminum Phosphoric TEAOH HF ZnO:Al₂O₃:H₃PO₄:R:H₂O = 27 NitrateSulfate Acid 0.5:16:32:55:150 Zeolite Magnesium Aluminum Phosphoric TEAMgO:Al₂O₃:H₃PO₄:R:H₂O = 28 Nitrate Nitrate Acid 0.5:17:32:55:150 ZeoliteCobalt Aluminum Phosphoric TEA HF SiO₂:Al₂O₃:H₃PO₄:R:H₂O = 29 NitrateSulfate Acid 0.4:18:32:55:150 Temperature of Hydrothermal DesorptionPeak Sample Temperature Point of Mediate Strong Number (° C.) Time (Day)Acid Amount Acid on NH₃-TPD (° C.) Zeolite 180 1 0.004 344 23 Zeolite150 4 0.11 357 24 Zeolite 160 4 0.012 347 25 Zeolite 170 2.5 0.07 343 26Zeolite 190 1 0.0506 360 27 Zeolite 200 1 0.178 357 28 Zeolite 170 0.70.255 363 29

III. Catalyst Preparation

The catalyst A and the catalyst B in the required ratio are added to thecontainer to achieve the purposes of separation, crushing, uniformmixing and the like, through one or more than one of extrusion force,impact force, shear force and friction force generated by high-speedmotion of the material and/or the container, and realize conversionamong mechanical energy, thermal energy and chemical energy byregulating the temperature and the atmosphere of carrier gas, therebyfurther enhancing the interaction between different components.

In the mechanical mixing process, the mixing temperature can be set as20-100° C., and the mechanical mixing process can be conducted in anatmosphere or directly in the air. The atmosphere is one or more of: a)nitrogen and/or inert gas; b) mixed gas of hydrogen, nitrogen and/orinert gas, with the volume ratio of hydrogen in the mixed gas being5-50%; c) mixed gas of carbon monoxide, nitrogen and/or inert gas, withthe volume ratio of carbon monoxide in the mixed gas being 5-20%; and d)mixed gas of oxygen, nitrogen and/or inert gas, with the volume ratio ofoxygen in the mixed gas being 5-20%. The inert gas is one or more ofhelium, argon and neon.

Mechanical stirring: mixing the catalyst A and the catalyst B with astirring rod in a stirring tank; and regulating the mixing degree andthe relative distance of the catalyst A and the catalyst B bycontrolling stirring time (5 min-120 min) and rate (30-300 r/min).

Ball milling: Rolling the abrasive and the catalysts at a high speed ina grinding tank thus producing strong impact and milling on thecatalysts to achieve the effects of dispersing and mixing the catalyst Aand the catalyst B. The ratio of the abrasive (which is stainless steel,agate and quartz; and the size range is 5 mm-15 mm) to the catalysts(the mass ratio scope is 20-100:1) is controlled to regulate theparticle size and the relative distance of the catalysts.

Shaking table mixing: premixing the catalyst A and the catalyst B andplacing the catalysts into the container; realizing the mixing of thecatalyst A and the catalyst B by controlling the reciprocatingoscillation or circumferential oscillation of the shaking table; andrealizing uniform mixing and regulating the relative distance byregulating oscillation speed (range: 1-70 r/min) and time (range: 5min-120 min).

Mechanical grinding: premixing the catalyst A and the catalyst B andplacing the catalysts into a container; and under a certain pressure(range: 5 kgf/cm²-20 kgf/cm²), making the ground and the mixed catalystsdo relative motion (speed range: 30-300 r/min) to achieve the effects ofregulating the particle size and the relative distance of the catalystsand realizing uniform mixing.

Specific catalyst preparation and parameter features are shown in Table6.

TABLE 6 Preparation of Catalysts and Parameter Features Compounding Modeand Condition Mechanical Ball Milling Shaking Grinding MechanicalAbrasive Table Pressure Geometrical Stirring Material, Oscillation (kg)and Center Weight Rate Size Range Speed Relative Distance of A CatalystCatalyst Catalyst Ratio of A (r/min) and and Catalyst (r/min) and MotionRate and B Number Component A Component B to B Time (min) Mass RatioTime (min) (r/min) Particles A ZnO1 Zeolite 1 0.33  5, 30 3 mm B ZnO 2Zeolite 2 0.5 100, 250 500 μm C ZnO3 Zeolite 3 2 5 mm 52 μm stainlesssteel ball, 50:1 D ZnO4 Zeolite 4 1 6 mm 8 μm stainless steel ball, 60:1E ZnO 5 Zeolite 5 1 5, 10 2 mm F ZnO 6 Zeolite 6 3 60, 100 600 μm G ZnO7 Zeolite 7 3 5, 30 300 μm H ZnO 8 Zeolite 8 1 100, 300 400 μm I spinel1 Zeolite 9 5 6 mm agate 30 μm ball, 100:1 spinel 2 Zeolite 10 1 70, 100500 μm K spinel 3 Zeolite 11 3 15, 200 150 μm L spinel 4 Zeolite 12 0.3320, 300 100 μm M spinel 5 Zeolite 13 1 100, 300 400 μm N MnO 1 Zeolite14 3 6 mm 15 μm quartz, 100:1 O MnO 2 Zeolite 15 0.33 6 mm 15 μm quartz,100:1 P MnO 3 Zeolite 16 1 10, 100 100 μm Q dispersed Zeolite 17 1 100,250 2 mm oxide 1 R dispersed Zeolite 18 3 5 mm 50 μm oxide 2 stainlesssteel ball, 50:1 S dispersed Zeolite 19 1 10, 100 100 μm oxide 3 Tdispersed Zeolite 20 4 50, 60  1 mm oxide 4 U dispersed Zeolite 21 3 10,100 100 μm oxide 5 V dispersed Zeolite 22 20 5 mm 5 μm oxide 6 stainlesssteel ball, 100:1 W ZnO1 Zeolite 23 0.5  5, 30 3 mm X ZnO 2 Zeolite 24 1100, 250 500 μm Y ZnO3 Zeolite 25 3 5 mm 52 μm stainless steel ball,50:1 Z ZnO4 Zeolite 26 1.5 6 mm 8 μm stainless steel ball, 60:1 Z1 ZnO 5Zeolite 27 2.5 5, 10 2 mm Z2 ZnO 6 Zeolite 28 1.5 60, 100 600 μm Z3 ZnO7Zeolite 29 2 5, 30 300 μm Z4 MnO 1 Zeolite 1 16 100, 200 400 μm Z5 ZnO 1Zeolite 1 0.1 20, 100 500 μm Z6 dispersed Zeolite 1 1 20, 300 100 μmoxide 1 Z7 spinel 1 Zeolite 1 1.5  60, 100 2 mm Z8 ZnO1 Zeolite 9 4 5 mm15 μm stainless steel ball, 50:1 Z9 MnO 1 Zeolite 2 4.5 50, 120 500 μmZ10 dispersed Zeolite 3 2.5 10, 200 200 μm oxide 1 Z11 spinel 1 Zeolite4 3 20, 200 150 μm Comparison 1 ZnO 9 Zeolite 1 3 20, 30  2 mmComparison 2 Zn 10 Zeolite 1 2  60, 100 2 mm

Example of Catalytic Reactions

A fixed bed reaction is taken as an example, but the catalyst is alsoapplicable to a fluidized bed reactor. The apparatus is equipped withgas mass flow meters and online product analysis chromatography (thetail gas of the reactor is directly connected with the metering valve ofchromatography, and thus periodic and real-time sampling and analysiswill be achieved).

2 g of the above catalyst in the present invention is placed in a fixedbed reactor. The air in the reactor is replaced with Ar; and then thetemperature is raised to 300° C. in the H₂ atmosphere, and then theinlet gas is switched to the syngas (H₂/CO molar ratio=0.2-3.5). Thepressure of the syngas is 0.5-10 MPa. The temperature is raised toreaction temperature of 300-600° C., and the space velocity of thereaction raw gas is regulated to 500-8000 ml/g/h. On-line chromatographyis used to detect and analyze the product.

The reaction performance can be changed by changing the temperature,pressure, space velocity and H₂/CO molar ratio in the syngas. The sumselectivity of propylene and butylene is 30-75%. The selectivity oflight olefins (the sum of ethylene, propylene and butylene) is 50-90%.Due to the low hydrogenation activity of the surface of the metalcomposite of the catalyst, a large amount of methane will be avoided andthe selectivity of methane is low. Table 7 lists specific applicationand effect data of the catalysts.

TABLE 7 Specific Application and Effect Data of Catalysts H₂/CO LightPropylene and Temperature Molar Pressure CO olefins CH₄ ButyleneEmbodiment Catalyst GHSV (h⁻¹) (° C.) Ratio (MPa) Conversion %Selectivity % Selectivity % Selectivity % 1 A 2500 410 2 3.5 13.5 71.813.2 47.1 2 B 3000 400 3.5 0.9 27.3 65.5 5.3 43.5 3 C 3000 360 3 2.542.5 70.5 14.2 55.3 4 D 8000 370 2 10 38.6 69.6 14.9 45.1 5 E 1000 4703.5 1.5 20.1 85.8 13.5 71.3 6 F 2000 400 3.5 7 33.3 78.8 6.6 54.3 7 G3000 380 1.5 2.5 10.3 81.2 11.7 68.6 8 H 500 370 2.5 5 18.6 78.4 9.864.3 9 I 2300 370 1 3.5 22.3 61.4 14.2 42.6 10 J 2000 410 2.5 8 33.384.7 11.5 71.9 11 K 1000 430 2.5 3 45.7 75.2 9.1 56.3 12 L 2500 520 1 415.2 77.2 14.5 57.7 13 M 3000 480 0.5 9 11.5 79.5 13.2 55.1 14 N 3100470 3 6 40.2 55.5 12.1 44.5 15 O 3200 450 1.5 5 14.3 60.9 13.2 46.3 16 P3000 450 2.5 5 13.8 75.6 8.9 41.4 17 Q 3000 350 3.5 5 37 72.2 8.6 44.318 R 2100 350 2 7 18.6 59.8 10.4 40.2 19 S 2500 400 1 6 19.6 70.8 10.745.7 20 T 4000 400 2 4 30.3 76.1 9.4 51.0 21 U 3500 400 3 3 16.4 67.811.2 43.4 22 V 3000 450 2.5 4 21.2 70.4 12.3 44.8 23 W 2500 410 2 3.511.3 85.3 8.9 71.7 24 X 3000 400 3.5 0.9 15.7 75.3 7.7 60.9 25 Y 3000360 3 2.5 25.7 60.7 11.7 49.3 26 Z 8000 370 2 10 38.7 76.8 9.7 61.2 27 Z1 1000 470 1.5 1.5 12.5 85.1 10.8 72.8 28 Z 2 2000 400 3.5 7 26.9 73.312.3 60.7 29 Z 3 3000 380 1.5 2.5 11.3 65.7 14.9 49.1 30 Z 4 2000 400 33.5 30.2 74.3 8.4 40.9 31 Z5 2500 400 0.3 10 16.8 70.1 5.3 40.0 32 Z63000 350 3 4 35.6 75.0 10.3 41.2 33 Z7 4500 400 2.5 3 21.8 65.3 12.243.2 34 Z8 4000 400 3 4 28.5 55.8 13.0 42.3 35 Z9 2000 350 2.5 3 38.962.3 8.7 48.7 36 Z10 4000 350 3 4 37.1 77.1 13.2 60.5 37 Z11 4200 4002.5 4 25.8 73.3 10.0 40.7 38 Reference 3000 320 0.5 1 1.9 31.0 31.0 29.2Example 1 39 Reference 2000 350 1 2 22.7 39.2 46.8 27.1 Example 2 40Reference 4000 450 3 3 30.5 26.8 22.6 12.9 Example 3 41 Reference 2000350 2.5 3 0.3 25.5 65.1 19.4 Example 4 42 Reference 2000 410 1.5 3 24.646.2 9.7 25.6 Example 5 43 Reference 3000 400 2 3.5 31.2 19.5 10.8 12.7Example 6 44 Reference 3000 450 2.5 4 8.6 43.6 37.9 28.8 Example 7 45Reference 3200 350 3 2.7 52.1 43.7 28.1 26.4 Example 8

In reference example 1, the catalyst component A is ZnO 9, and componentB is Zeolite 1.

In reference example 2, the catalyst component A is Zn 10, and componentB is Zeolite 1.

The component A in the catalyst adopted in reference example 3 is metalZnCo+Zeolite 1. The molar ratio of Zn to Co is 1:1. The mass ratio ofZnCo to Zeolite 1 is 1:1. Other parameters and the mixing process arethe same as those of catalyst A.

The catalyst adopted in reference example 4 is TiO₂ without surfaceoxygen vacancy+Zeolite 1. Other parameters and the mixing process arethe same as those of catalyst A.

The zeolite in the catalyst adopted in reference example 5 is acommodity SAPO-34 purchased from Nankai University Catalyst Factory,wherein the temperature of desorption peak of medium-strength acid onNH₃-TPD is 390° C.

The zeolite in the catalyst adopted in reference example 6 is acommodity ZSM-5 purchased from Nankai University Catalyst Factory,wherein the zeolite is of a full microporous structure and the Si/Alratio is 30.

Reaction results of reference examples 5 and 6 show that, thetopological structure and acid strength of CHA or AEI are crucial to themodulation of the selectivity of products.

The distance between the metal oxide and the zeolite in the catalystadopted in reference example 7 is 10 mm. Other parameters and the mixingprocess are the same as those of catalyst A.

The metal oxide in the catalyst adopted in reference example 8 islocated in porous channels of the zeolite and is in close contact withthe zeolite. Other parameters and the like are the same as those ofcatalyst A.

Results of reference examples 7 and 8 show that, the distance betweencomponent A and component B is also crucial to product selectivity.

In the reference technology of the document (Jiao et al., Science 351(2016) 1065-1068), the acid amount of the adopted SAPO-34 zeolite waslarge. The amount of the medium-strength acid reached 0.32 mol/kgaccording to the NH₃-TPD test. Therefore, when the conversion increasedto 35%, the selectivity of light olefins was 69%, the selectivity oflight paraffins was 20%, o/p decreased to 3.5 and the selectivity ofpropylene and butylene was 40-50%.

It is observed from the above table that, the structure of the zeoliteincluding the topologies, acid strength and acid amount of CHA&AEI, andthe matching of the distance between the metal oxide and the zeolite arecrucial and directly affect the conversion of carbon monoxide and theselectivity of propylene and butylene.

1. A catalyst, characterized in that: the catalyst is a compositecatalyst A+B and is formed by compounding catalyst component A andcatalyst component B in a mechanical mixing mode; the active ingredientof catalyst component A is active metal oxide; catalyst component B is azeolite of CHA and/or AEI topology; the active metal oxide is one ormore than one of MnO, MnCr₂O₄, MnAl₂O₄, MnZrO₄, ZnO, ZnCr₂O₄, ZnAl₂O₄,CoAl₂O₄ and FeAl₂O₄.
 2. The skeleton element composition of the zeoliteof CHA and AEI topologies may be one or more than one of Si—O, Si—Al—O,Si—Al—P—O, Al—P—O, Ga—P—O, Ga—Si—Al—O, Zn—Al—P—O, Mg—Al—P—O andCo—Al—P—O; a molar ratio of (Si+Zn+Mg+Co) to (Al+Ga) in the zeolitecomposition Si—O of the CHA topology and in the skeleton elementcomposition outside is less than 0.6, preferably 0.001-0.48; and a molarratio of (Si+Zn+Mg+Co) to (Al+Ga) in the zeolite composition Si—O of theAEI topology and in the skeleton element composition outside is lessthan 0.6, preferably 0.001-0.48.
 3. The catalyst according to claim 1,wherein the zeolite has the characteristic of medium-strength acid, andthe amount of medium-strength acid sites is 0-0.3 mol/kg, preferably0.003-0.2 mol/kg, and more preferably 0.003-0.06 mol/kg, wherein thepeak temperature range corresponding to the desorption peak of NH₃-TPDfor medium-strength acid is 275-500° C.; and by using acetone as theprobe molecule, the chemical shift of ¹³C-NMR is in the range of 210-220ppm.
 4. The catalyst according to claim 1, wherein Component A ispreferably one or more than one of MnO, MnCr₂O₄, MnAl₂O₄, MnZrO₄,ZnAl₂O₄, CoAl₂O₄ and FeAl₂O₄.
 5. The catalyst according to claim 1,wherein a spacing between geometric centers of the active metal oxide ofthe catalyst component A and the particle of the catalyst component B is5 μm-40 mm; when the Component A is selected from MnO, MnCr₂O₄, MnAl₂O₄and MnZrO₄, the spacing between particles of the Component A and theComponent B is preferably 100 μm-5 mm and more preferably 200 μm-4 mm;when the component is selected from ZnAl₂O₄, CoAl₂O₄ and FeAl₂O₄, thespacing between particles of the Component A and the Component B ispreferably 200 μm-3 mm; and when the component is selected from ZnCr₂O₄,the spacing between particles of the Component A and the Component B ispreferably 500 μm-3 mm.
 6. The catalyst according to claim 1, wherein aweight ratio between the active ingredient in the catalyst component Aand the catalyst component B is within the range of 0.1-20 times, andpreferably 0.3-5.
 7. The catalyst according to claim 1, wherein theactive metal oxide is composed of grains with a size of 5-30 nm, and alarge amount of oxygen vacancies exist within a distance range of 0.3 nmfrom the surfaces of the grains to the internal direction of the grains,wherein the molar weight of oxygen atoms occupies a value less than 80%of the oxygen molar content in theoretical stoichiometric ratio,preferably, 80%-10%, more preferably 60%-10% and most preferably50%-10%; the surface oxygen vacancies are defined as: 100%-percent ofthe molar weight of oxygen atoms in theoretical stoichiometric ratio ofoxygen molar weight; and corresponding oxygen vacancy concentration ispreferably 20%-90%, more preferably 40%-90% and most preferably 50%-90%.8. The catalyst according to claim 1, wherein a dispersing agent is alsoadded to the catalyst A; the dispersing agent is one or more than one ofAl₂O₃, SiO₂, Cr₂O₃, ZrO₂ and TiO₂; the active metal oxide is dispersedin the dispersing agent; and the content of the dispersing agent in thecatalyst A is 0.05-90 wt %, and the balance is the active metal oxide.9. The catalyst according to claim 1, wherein H may be connected or notconnected to O element of the zeolite skeleton; the H may be entirely orpartially replaced by one or more than one of Na, Ca, K, Mg, Ge, Zr, Zn,Cr, Ga, Sn, Fe, Co, Mo and Mn by ion exchange; and the total molar ratioof the substitute metal to oxygen is 0.0002-0.001.
 10. A method forpreparing light olefins using direct conversion of syngas, whereinsyngas is used as reaction raw material; a conversion reaction isconducted on a fixed bed or a moving bed; and the adopted catalyst isthe catalyst of claim 1; and the pressure of the syngas is 0.5-10 MPa;reaction temperature is 300-600° C.; space velocity is 300-10000 h⁻¹;and the molar ratio of syngas H₂/CO for reaction is 0.2-3.5, andpreferably 0.3-2.5.
 11. The catalyst according to claim 2, wherein thezeolite has the characteristic of medium-strength acid, and the amountof medium-strength acid sites is 0-0.3 mol/kg, preferably 0.003-0.2mol/kg, and more preferably 0.003-0.06 mol/kg, wherein the peaktemperature range corresponding to the desorption peak of NH₃-TPD formedium-strength acid is 275-500° C.; and by using acetone as the probemolecule, the chemical shift of ¹³C-NMR is in the range of 210-220 ppm.12. The catalyst according to claim 6, wherein H may be connected or notconnected to O element of the zeolite skeleton; the H may be entirely orpartially replaced by one or more than one of Na, Ca, K, Mg, Ge, Zr, Zn,Cr, Ga, Sn, Fe, Co, Mo and Mn by ion exchange; and the total molar ratioof the substitute metal to oxygen is 0.0002-0.001.